1. Technical Field
The present invention relates to a recording apparatus represented by a facsimile, a printer or the like.
2. Related Art
In a recording apparatus represented by a facsimile, a printer or the like, a paper transportation unit that accurately transports recording paper fed from a paper feeding section that feeds the recording paper, as an example of a medium, below a recording head may be configured of a driving roller that is rotated by a driving source and a driven roller that is driven to rotate by pressing the recording paper between the driving roller and the driven roller.
Most of the driving rollers are configured by including a high-friction layer on an outer peripheral surface of a shaft body (for example, a metal shaft) and the high-friction layer is formed of wear-resistant particles and a coating material in which the wear-resistant particles are adhered and held on the outer peripheral surface of the shaft body (for example, see JP-A-2012-121648).
Further, when a paper jam occurs in the middle of a transportation path, when the recording paper is interposed between the driving roller and the driven roller, workability is lowered when removing the recording paper. Thus, a configuration that takes into account the workability of the paper removal and releases (separates) the driven roller from the driving roller is adopted in the related art (for example, see JP-A-2005-112490).
Furthermore, if an object to be recorded is a disk-shaped medium, there is a case where a roller mark is caused by the driven roller coming into contact with the disk-shaped medium. Thus, a recording apparatus disclosed in JP-A-2012-116203 includes a configuration in which each of positions of a plurality of driven rollers is displaced in a contact and separation direction with respect to the driving roller.
The recording apparatus disclosed in JP-A-2012-121648 is made by considering convenience of paper jam recovery work and the recording apparatus disclosed in JP-A-2005-112490 is made by considering the transportation of the disk-shaped medium, however they still have problems as described below.
That is, when recording on the recording paper such as plain paper, a plurality of driven rollers are driven to rotate by coming into contact with the paper and some driving rollers located outside a paper region are driven to rotate by directly coming into contact with the driving roller. However, since the driven rollers of the latter come into contact with the driving roller having the high-friction layer on the outer peripheral surface thereof, that is, the driving roller having a great number of fine unevenness on the outer peripheral surface thereof, as a result, a harsh noise may occur.
Particularly, if the size of the paper is small, since the number of the driven rollers or the contact region coming into contact with the driving roller increases, the degree of the noise becomes more remarkable. Therefore, in recent years, in ink jet printers, noise reduction is further required and it is preferable that occurrence of noise, as described above, be effectively suppressed.